Why Do Websites Use Web Cookies?

Have you ever noticed how you can log in to a website and then, the next time you visit that site, it logs you in automatically? If you’ve ever done any Internet shopping, you might have also noticed how you can put items into a shopping cart, leave the website, and return to find those items still in your cart. You can thank web cookies for these conveniences.

Cookies were invented in 1994 by a 24-year-old programmer named Lou Montulli, who also claims to have invented the <blink> tag. A cookie is a small data file that certain web sites write to your hard drive when you visit them. A cookie is a simple piece of text. It is not a program or a plug-in. It cannot be used as a virus, and it cannot access your hard drive or read cookie files created by other sites, although that technology is probably under development.

A cookie file can contain information such as a user ID that a web site uses to track the pages you visit, but the only personal information a cookie can contain is information which you supply yourself. Cookies were designed to be a reliable mechanism for websites to remember stateful information (such as items added in the shopping cart in an online store) or to record the user’s browsing activity (including clicking particular buttons, logging in, or recording which pages were visited in the past).

When you visit a website, the website sends a web cookie to your computer to be saved in a file. Internet cookies consist of information saved as text. This information can keep track of a wide variety of things, such as usernames, passwords, visits, and articles or products viewed.

Web cookies go by various other names, such as HTTP cookies, computer cookies, internet cookies, and browser cookies. The term “cookie” is actually a shortened version of the term “magic cookie,” which refers to a packet of data that a computer receives and sends back without altering the data.

Websites store cookies on your computer to help keep track of your visits and online activity. Although that might sound a bit intrusive, it can be very helpful. For example, would you want to have to log in to a site you visit frequently every time you jump online? Shopping online would also be much more difficult without cookies.

Some people find cookies to be too intrusive, however. If you’ve ever shopped for a suitcase online, only to visit another site or check your email to see advertisements for suitcases and travel packages, then you’ve experienced the power of advertising and tracking networks that use cookies to track your activity across the Internet.

If you think cookies are an invasion of your privacy, every Internet browser allows you to customize your settings to limit or eliminate cookies. Be warned, though. Completely eliminating cookies can make some websites very difficult to navigate!

Content for this question contributed by Robert Parker, resident of University Heights, Cuyahoga County, Ohio, USA